Geseilschaft



Sept. 16, 1924. 1,509,026

7 J. PFRETZSCHNER ELECTRIC TIME swI'rcH Filed March 24, 1922 trunnions a Patented Sept. 16, 1924.

UNITED STATES I 1,509,026 PATENT OFFICE.

JAKOB PFRETZSCHNER, 0F ESSEN, GERMANY, ASSIGNOR T0 FRIED. KRUPP AKTIEN- GESELLSCHAFT, OF ESSEN-ON-THE-RUHR, GERMANY.

ELECTRIC TIME SWITCH.

Application filed March 24, 1922. Serial No. 546,379.

To all whom it may concern:

Be it known that I, J AKOB PFRETZSCHNER, residing at Essen, Germany, a citizen of the German Republic, have invented a certain new and useful Improvement in Electric Time Switches, of which the following is a specification.

This invention relates to so-called electric time switches, that is to say, switches which break the circuit at a certain time after the moment when the circuit was closed. The object of the invention is to provide such a time switch which is distinguished by its simplicity of construction and sureness of operation. This object is-at-tained, according to the invention, by the provision of a circuit closing part on a freely oscillatable member acted upon by a spring and which is connected by a spring with a heavy member also mounted so as to turn freely.

The drawing diagrammatically illustrates, by way of example, a time switch for electric welding apparatus;

Fig.1 is an elevation and partial section of the switch and the parts in consideration, of the welding apparatus.

Fig. 2 is a section on 22 from the right, and

Fig. 3 is a partial view, similar to Fig. 1, of the switch with its parts in another position.

On acylindrical disk A is mounted an insulated circuit closer a in the form of a blade. The disk A is rotatably mounted by in a stationary bearing support B (Fig. On one of said trunnions a is loosely mounted a hollow cylindrical casing C, which is connected with the disk A by a spiral spring D, (Fig. 2), one end of which is fastened to the inside of the casing and at the other end to the trunnion a The disk A carries on its periphery a lug a which projects in lateral direction partially over the periphery of the casing C and has two opposite abutment faces a and a In the path of the lug (1 lies a lug 0 carried by the casin C, which can engage by its face 0 with the face a The lugs a and 0 constitute, therefore, a one-way clutch for the disk A and casing C. Diametrically opposite the lug a is an ear a to which is fastened one end of a spring E, the other end of which is secured to a fixed part. With the of Fig. 1, seen lug a is adapted to engage a slidable bolt G,

acted upon by a spring F, and which, in the position of rest of the switch shown in Fig. 1, rests with its end on the face a of the In a To the other end of the bolt G is pivote a spring pressed pawl I-I (Fig. 1). In the position of Fig. 1, the pawl H rests with its nose h? on a lug 21 formed on a rod J, and has an inclined surface If, in the path of which lies a fixed abutment K which acts to swing the pawl in the direction of the arrow g about its axis and release it from the lug i when the bolt G is slid in the direction of the arrow as. Pivotally connected to the upper end of the rod J is a two-armed handlever M and a lever P is connected to its lower end through an interposed spring N. The other end of the lever trode of the welding apparatus the other electrode 9 being fixed. These electrodes are connected in the secondary circuit Q, of a transformer, the primary winding R of which is connected to a source of alternating current by wires P in which are inserted two spring tongues r forming a break in the circuit which can be bridged by the circuit closer a P carries one elec- In the operation of the switch, the lever M is swung in the direction of the arrow 2 which, through the rod J, thereby moved in the direction of the arrow 00, and the spring N, which is not at this time stretched, turns the lever P until the electrode 3) contacts the work (not shown) resting on the electrode 9 As the lever M continues to swing, the rod J is further raised and the spring N is expanded, so that the electrode p is pressed with increasing force on the work resting between the electrodes. In the said displacement of the rod J, the bolt G is likewise moved in the direction of arrow a: by the engagement of the lug 73 under the nose k of the pawl H and against the pressure of the spring F which is tensioned thereby. When the inclined surface k of the pawl H comes into engagement with the abutment K, the pawl H is swung in the direction of the arrow 3 and its nose 72. is finally disengaged from the lug 6 At this instant, the bolt G is suddenly slid in the opposite direction to arrow 00, by the expansion of the spring F and strikes the face a of the lug a whereby the disk A and the casing 0, connected to it by the lugs a and 0 are turned in the direction of arrow '2) (Fig. 1), putting the spring E under tension. This brings the circuit closer blade at into the position of Figs. 2 and 3, in which it bridges the gap in the circuit of the primary winding R of the transformer R Q, at the spring tongues T In this angular position the disk A is held against the pull of the spring E, by the spiral spring D and by the friction between the tongues r and the blade a". The casing C, acting as a fiy-mass, is carried further 1n the direction of arrow '0 by momentum and comes finally 'into the position shown in Fig. 3, in which its lug c has moved through a certain angle away from the lug a In this further rotation of the casing C, the spiral sprlng D has been tensioned so strongly that the energy stored in the casing C has exhausted itself and the latter has consequently come to rest (see Fig. 3). Immediately thereafter, the spring D begins to re-expand and the casing therefore begins to turn backwards. As soon as the lug has come, in this backward movement, with its face 0 into contact with the face a of the lug a the disk A begins to move backwards also, while the spring E contracts, so that the blade (1 leaves the tongues 1' and the circuit is automatically broken. In the further backward movement, the parts C and A finally come again into the angular position of Fig. 1, in which they are ready to repeat the operation.

The length of time between the moment of closing the circuit and the automatic breaking of the same depends upon the amount of the fly-mass C, the strength of the spring D and the force of the blow exerted by the bolt G, and can be easily varied by varying any one of those elements. It is also possible to provide an adjustable abutment (not shown) in the path of the lug a, which would limit'the angular throw of the fiy-mass C and thereby vary said length of time. Without changing the spirit of the invention at all, it is possible to omit the lug c on the fly-mass C. The provision of said In 0 has the advantage, however, that the disK A and fly-mass 0 turn with the same angular velocity at the beginning of their oscillation.

Claims.

1. In a time closing switch, a variably operated means for a switch opening and closing action, a spring operated tripping means automatically released for standardized action by a predetermined amplitudinal movement of said variably operated means and a switching device having an opening and closing cycle of operations operated by the predetermined hammer blow action-of said tripping means.

2. In a time closing switch, a variably operated means for a switch'opening and closing action, a spring operated tripping means automatically released for. standardized action by a predetermined amplitudinal movement of said variably operated means and a switching device having an opening and closing cycle of operations operated by the predetermined hammer blow action of said tripping means, said switching device comprising a plurality of similarly abutting parts with a lost motion connection between them and means for returning said parts the predetermined hammer blow action of said tripping means, said switching device comprising a plurality of similarly abutting parts with a lost motion connection between them and means for returning said parts to normal abutting relationship after being differentially impelled together by said hammer blow action, one of said parts carrying a circuit closing element for closing a circuit on a predetermined movement of said part.

4. In subcombination a switching and unswitching means comprising two abutting parts with a lost motion connection between them, said parts having the mechanical characteristic of a differential kinetic response to a given impulsive action, and means for returning said parts to normal abutting relationship.

5. In subcombination a switching and unswitching means comprising two abutting parts with a lost motion connection between them, said parts having the mechanical characteristic of a diiferential kinetic response to a given impulsive action, and means for returning said parts to normal abutting relationship, one of said parts carrying a circuit closing element for closing a circuit on a predetermined movement of said part.

6. In subcombination a switching and unswitching means comprising two abutting parts with a lost motion spring connection between them, said parts having the mechanical characteristic of a differential kinetic response to a given impulsive action,

a switching device having an opening and closing cycle of operations operated by the predetermined hammer blow action of said tripping means, said switching device comprising a plurality of similarly abutting parts with a lost motion connection between them and means for returnin said parts to normal abutting relationship after being differentially impelled together by said hammer blow action, one of said parts carrying a circuit closing element for closing one side of a transformer circuit on a predetermined movement of said part, and switch closing means on said first named means for closing the other side of said transformer.

8. In a time closing switch, a variably operated means for a switch opening and closing action, a spring operated tripping means automatically released for standardized act-ion by a predetermined amplitudinal movement of said variably operated means and a switching device having an opening and closing cycle of operations operated by the predetermined hammer ,blow action of said tripping means, said switching device comprising a plurality of similarly abutting parts with a lost motion connection between them and means for returning said parts to normal abutting relationship after being differentially impelled together by said hammer blow action, one of said parts carrying a circuit closing element for closing a circuit on a predetermined movement of said part, and a circuit means-for said circuit closing element.

9. In subcombination a switching and unswitching means comprising two abutting parts with a lost motion connection between them, said parts having the mechanical characteristic of a differential kinetic response to a given impulsive action, and means for returning said parts to normal abutting relationship, one of said parts carrying a circuit closing element for closing a circuit on a predetermined movement of said part, and a circuit means for said circuit closing element.

10. In a time closing switch, a variably operated means for a switch opening and closing action, a spring operated tripping means automatically released for standardized action by a predetermined amplitudinal -movement of said variably operated means and a switching device having an opening and closing cycle of operations operated by the predetermined hammer blow action of said tripping means, said switching device comprising a plurality of similarly abutting parts with a lost motion connection between them and means for returning said parts to normal abutting relationship after being difi'erentially impelled together by said hammer blow action, one of said parts carrying a circuit closin element for closing one side of a transf drmer circuit on a predetermined movement of said part, and switch closing means on said first named means for closing the other side of said transformer, and a transformer havin a primary circuit means for said circuit 0 osing element and a secondary circuit means for said switch closing means.

The foregoing specification signed at Essen, Germany, this 17th day of February,

J AKOB PFRETZSGHNER. 

